Zincke Reaction Research Articles

Design, synthesis, and biological evaluation of novel, centrally-Acting thyrotropin-Releasing hormone analogues

Novel, metabolically stable and centrally acting TRH analogues with substituted pyridinium moieties replacing the [His 2] residue of the endogenous peptide were prepared by solid-phase Zincke reaction. The 1,4-dihydropyridine prodrugs of these analogues obtained after reducing the pyridinium moiety were able to reach the brain and maintain a sustained concentration of the charged, degradation-resistant analogues formed after enzymatic oxidation of the prodrug, as manifested by the analeptic action measured in mice. Among the four analogues reported, compound 2a showed the highest potency and longest duration of action in reducing the pentobarbital-induced sleeping time compared to the parent TRH. No binding to the endocrine TRH-receptor was measured for 2a; thus, this compound emerged as a potent, centrally acting TRH analogue.

Polymer site–site interactions: mechanistic implication in the solid-phase Zincke reaction

Mechanistic aspects of the solid-phase Zincke reaction have been investigated using Wang resins; a proton transfer mechanism is proposed which obviates the need for covalent bond site–site interactions.

New developments in asymmetric Bradsher cycloadditions: use of chiral dienes

Several serinol derivatives have been prepared and condensed following the Zincke reaction with 2,7-naphthyridine. The resulting naphthyridinium salts were engaged in Bradsher cycloadditions with enol ethers and afforded tetracyclic adducts, potential synthetic precursors of manzamine A alkaloid.

The solid-phase Zincke reaction: preparation of omega-hydroxy pyridinium salts in the search for CFTR activation.

A study of structural modifications of MPB-07 was undertaken as part of a synthetic program aimed at discovering small molecules with CFTR activation potential. Solid-phase synthesis techniques were used to prepare derivatives of MPB-07 employing the Zincke reaction for the construction of aromatic, quaternary ammonium salts such as those found in 2 or 3. In this transformation, primary amines react with highly electrophilic N-2,4-dinitrophenylpyridinium (DNP) salt 4 to afford pyridinium salt 8 with release of 2,4-dinitroaniline 6. Thus, the reaction of 1-(2,4-dinitrophenyl)pyridinium salts with various polymer-bound amino ethers, followed by cleavage from the resin, delivers the desired salts in good yield and high purity.

The Zincke's Reaction: A New Alternative for the Preparation of L-[2-(3-Indol)Ethyl]-Alkylpyridinium Chloride Derivatives

The Zincke's salts 3 (a-f) were prepared and used for the synthesis of 1-[(2-(3-indol)-ethyl]alkylpyridinium chloride derivatives 5 (a-f) in high yields.

ChemInform Abstract: New Chiral Isoquinolinium Salt Derivatives from Chiral Primary Amines via Zincke Reaction.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of Some "Abbreviated" NAD+ Analogues

Four new "abbreviated" NAD+ analogues with hydroxymethyl or carboxyl function as a substituent of an aliphatic chain linking the adenine and nicotinamide moieties were prepared using the Zincke reaction as the key step. As intermediates several new acyclic nucleoside analogues containing hydroxy, carboxyl, azido and amino group were prepared.

New Chiral Isoquinolinium Salt Derivatives from Chiral Primary Amines via Zincke Reaction

New Chiral Isoquinolinium Salt Derivatives from Chiral Primary Amines <i>via </i>Zincke Reaction

"Abbreviated" NAD+ Analogues Containinga Phosphonate Function

"Abbreviated" NAD+ analogues with anionic phosphonate function as a part of the link between the adenine and nicotinamide moieties, 9-(2-phosphonomethoxyethyl)adenine 2-(3-carbamoylpyridinium)ethyl ester (1a), (R)- and (S)-9-(2-phosphonomethoxypropyl)adenine 2-(3-carbamoylpyridinium)ethyl ester (1b and 1c), (RS)-9-(3-hydroxy-2-phosphonomethoxypropyl)adenine 2-(3-carbamoylpyridinium)ethyl ester (1d), and (S)- and (R)-1-[3-(adenin-9-yl)-2-phosphonatomethoxypropyl]-3-carbamoylpyridinium (2a and 2b), were prepared by multistep syntheses using the Zincke reaction in the last step.

Synthesis and chiroptical properties of some abbreviated NAD+ analogues

Abstract Four novel “abbreviated” NAD + analogues were prepared by the Zincke reaction. The acyclic chain joining the bases of the analogues bears two stereogenic centers with hydroxyl groups in the both erythro and threo mutual relations. The CD spectra of all stereoisomers were measured and discussed.

Synthesis of Base-Modified "Abbreviated" NAD Analogues

The "abbreviated" model of NAD, 1-[3-(adenin-9-yl)-2-hydroxypropyl]-3-carbamoylpyridinium chloride (VIIIa), and its 2,6-diaminopurine (VIIIb), 3-deazaadenine (VIIIc), guanine (VIIId) and cytosine (VIIIe) analogues were prepared by the Zincke reaction. The (R)-isomer of the adenine model VIIIa (compound IX) was prepared for chiroptical studies. As shown by NMR, UV and CD spectra, neither in dimethyl sulfoxide nor in water any intramolecular π-π interactions exist between the heteroaromatic systems.

Zincke's Reaction with Chiral Primary Amines: A Practical Entry to Pyridinium Salts of Interest in Asymmetric Synthesis

The scope of Zincke's synthesis of pyridinium salts using various chiral primary amines and mono- or dialkylpyridines substituted at positions 3, 4 or 5 has been investigated. Salts 6a-f, 9a-i, and 10b,e,h-j were obtained in excellent yields. The results support the accepted mechanism for Zincke's reaction and shows the influence of the solvent on the course of this reaction.

ChemInform Abstract: Novel Models of NADH in the 3‐Oxazolyl‐1,4‐dihydropyridine Series: Synthesis, Reactivity and Role of Complexation in the Reactivity.

AbstractA new class (X) of the title NADH models is prepared by regioselective addition reaction of the pyridine (I) (→ (III)), subsequent oxidation (→ (IV)), quaternization either directly (→ (VI)) or through Zincke's reaction (→ (IX)), and reduction.

Nouveaux modèles du NADH en série oxazolyl-3 dihydro-1,4 pyridine: synthèse, réactivité, rôle de la complexation dans la réactivité

A new class of NADH models is described: they contain the 3-oxazolyl-1,4-dihydropyridine structure. They have been synthesized by regioselective addition at the 4 position of organometallic derivatives (one of them bearing a chiral group) on 3-(4,4-dimethyl-2-oxazolyl)pyridine. The 1,4-dihydropyridine structure is obtained after quaternarization and reduction by sodium dithionite. Quaternarization through Zincke's reaction leads to models having a chiral group at the pyridine nitrogen. This chirality is necessary to induce asymmetry at the 4 carbon in the corresponding 1,4-dihydropyridine. This asymmetry plays an important role in the low enantioselectivity of reduction of a prochiral substrate such as methyl benzoylformate. The chemical reactivity of the models has been studied by performing the reduction of p-nitrobenzaldehyde in the presence of magnesium perchlorate. All models gave quantitative yields. However, reactions are slower than those performed, in the same conditions, with N-benzyl-1,4-dihydronicotinamide (BNAH). A 13C nmr study shows that this behaviour is probably a consequence of the high complexation of magnesium with the oxazoline moiety.

Stereospecific synthesis of chiral N-(p-methoxyphenylalky)pyridinium salts

A series of chiral N-(p-methoxyphenylalky)pyridinium salts (1)–(15) were prepared from their parent chiral (p-methoxyphenylalkyl)amines with retention of configuration by the Zincke reaction.

Fungicide Residues, Determination of Dyrene in Apples by Application of the Zincke Reaction

Fungicide Residues, Determination of Dyrene in Apples by Application of the Zincke Reaction

LXXXV.—A modification of Zincke's reaction

LXXXV.—A modification of Zincke's reaction